In a typical computer environment, a Local Area Network (LAN) allows for one or more computer servers to be connected to several computers such that the resources of each server are available to each of the connected computers. In this system, a dedicated keyboard, video monitor, and cursor control device may be employed for each computer and computer server.
To maintain proper operation of the LAN, the system administrator must maintain and monitor the individual servers and computers. This maintenance frequently requires the system administrator to perform numerous tasks from the user console located at each server or computer. For example, to reboot a computer or to add or delete files, the system administrator is often required to operate the server or computer from its local user console, which may be located at a substantial distance from the system administrator's computer. Therefore, to accomplish the task of system administration, the system administrator must often travel far distances to access the local user consoles of remotely located servers and computers.
As an alternative, dedicated cables may be installed from each remotely located server and computer to the system administrator's user console to allow the system administrator to fully access and operate the remote computer equipment. However, such an alternative requires substantial wiring and wire harnessing, both of which may require tremendous cost. Additionally, as the distance between the system administrator's user console and the remote computer equipment increases, a decrease in the quality of the transmitted signal often results. Thus, utilizing dedicated cables between the system administrator's user console and remote computer equipment is often not a feasible alternative.
Space is also an important concern for many networked computer environments, especially large-scale operations such as data-centers, server-farms, web-hosting facilities, and call-centers. These environments typically require space to house a keyboard, video monitor, and cursor control device for each piece of computer equipment and for all of the wiring required to connect and power these components. As more equipment is added to a computer network, it becomes more probable that the space required for the equipment and associated cabling will exceed the space allotted for the network. Therefore, network architecture, equipment size, and available space are important issues when designing an effective computer network environment.
One method of reducing the amount of space required to house a computer network is to eliminate any equipment (i.e., keyboard, video monitor, cursor control device, etc.) that is not essential for proper operation of the computer network. Elimination of this equipment also eliminates the wiring associated with such equipment. This equipment and its associated wiring may be eliminated if a system administrator is able to access the remote computers from one user console, thereby eliminating the dedicated equipment and its associated wiring. Elimination of this unnecessary equipment decreases the amount of space required for computer network environments.
A keyboard, video monitor, and mouse (“KVM”) switching system may be utilized to allow one or more user workstations to select and control any one of a plurality of remote computers via a central switching unit. Such systems are well known in the art and have been used by system administrators for at least 10 years. Specifically, a KVM switching system allows a system user to control a remote computer using a local user workstation's keyboard, video monitor, and cursor control device as if these local devices were directly connected to the remote computer. In this manner, a system user may access and control a plurality of remote computers, such as servers, from a single location (i.e., the location of the user workstation). The system user may select a specific remote computer to access or control using any one of a variety of methods known in the art. For example, the computer management system component can include an array of buttons where each button corresponds with the desired remote computer. Alternatively, a user can select the computer from a list displayed on a computer management system component's LCD or LED display, press one or more hot keys on the local user workstation's keyboard (e.g., F1, ALT-F1, F2, etc.), select the remote computer from a list displayed on the user workstation's monitor by pointing to it or scrolling to it using the user workstation's keyboard and/or cursor control device, etc.
The following references, which are discussed below, were found to relate to the field of computer management systems: Asprey U.S. Pat. No. 5,257,390 (“Asprey '390 patent”), Asprey U.S. Pat. No. 5,268,676 (“Asprey '676 patent”), Asprey U.S. Pat. No. 5,353,409 (“Asprey '409 patent), Perholtz et al. U.S. Pat. No. 5,732,212 (“Perholtz”), Chen U.S. Pat. No. 5,978,389 (“Chen '389 patent”), Chen U.S. Pat. No. 6,119,148 (“Chen '148 patent”), Fujii et al. U.S. Pat. No. 6,138,191 (“Fujii”), Beasley U.S. Pat. No. 6,345,323 (“Beasley”), and Wilder et al. U.S. Pat. No. 6,557,170 (“Wilder”).
The Asprey '390 patent, filed on Jul. 26, 1991 and issued on Oct. 26, 1993, discloses an extended range communications link for coupling a computer to a mouse, keyboard, and/or video monitor located remotely from the computer. The end of the link that is coupled to the computer has a first signal conditioning network (i.e., a network of circuitry that dampens the ringing and reflections of the video signals and biases them to a predetermined voltage level) that conditions the keyboard, video monitor and mouse signals. Conditioning the video monitor signals includes reducing their amplitude in order to minimize the “crosstalk” induced on the conductors adjacent to the video signal conductors during transmission of the video signals. This first signal conditioning network is coupled to an extended range cable having a plurality of conductors that transmits the conditioned signals, power, and logic ground potentials to a second signal conditioning network (i.e., a network of circuitry that terminates the video signals using a voltage divider and amplifies them), which restores the video signals to their original amplitude and outputs them to a video monitor.
The Asprey '676 patent, filed on Mar. 5, 1990 and issued on Dec. 7, 1993, discloses a communications link for use between a computer and a display unit, such as a video monitor, that allows these two components to be located up to three hundred (300) feet apart. An encoder located at the computer end of the communications link receives analog red, green, and blue signals from the computer and inputs each signal to a discrete current amplifier that modulates the signal current. Impedance matching networks then match the impedance of the red, green and blue signals to the impedance of the cable and transmit the signals to discrete emitter-follower transistors located at the video monitor end of the cable. Thereafter, these signals are amplified prior to inputting them to the video monitor. Concurrently, the horizontal synchronization signal is inputted to a cable conductor and its impedance is not matched to the impedance of the cable, thereby allowing the conductor to attenuate the horizontal synchronization signal and reduce noise radiation.
The Asprey '409 patent, filed on Jul. 19, 1990 and issued on Oct. 4, 1994, discloses an extended range communications link for transmitting transistor-transistor logic video signals from a local computer to a video monitor located up to a thousand feet (1,000) from the computer. The link includes a first signal conditioning circuit (i.e., a circuit that reduces the amplitude of the video signals, biases them to a selected potential, and applies them to discrete conductors of an extended cable) located at the computer end of the link for conditioning the received signals and transmitting them via the extended cable to a second signal conditioning circuit. The second signal conditioning circuit (i.e., a circuit that utilizes a threshold or pair of thresholds to effect reconstruction of the video signals prior to applying the signals to a video monitor) receives the transmitted video signals prior to inputting them to the video monitor. According to the Asprey '409 patent, performance of this process reduces the appearance of high frequency video noise on the keyboard clock conductor of the transmission cable, thereby preventing keyboard errors.
Perholtz, filed on Jan. 13, 1994 and issued on Mar. 24, 1998, discloses a method and apparatus for coupling a local user workstation, including a keyboard, mouse, and/or video monitor, to a remote computer. Perholtz discloses a system wherein the remote computer is selected from a menu displayed on a standard size personal computer video monitor. Upon selection of a remote computer by the system user, the remote computer's video signals are transmitted to the local user workstation's video monitor. The system user may also control the remote computer utilizing the local user workstation's keyboard and monitor. The Perholtz system is also capable of bi-directionally transmitting mouse and keyboard signals between the local user workstation and the remote computer. The remote computer and the local user workstation may be connected either via the Public Switched Telephone System (“PSTN”) and modems or via direct cabling.
The Chen '389 patent, filed on Mar. 12, 1998 and issued on Nov. 2, 1999, discloses a device for multiplexing the video output of a plurality of computers to a single video monitor. The system includes three sets of switches for receiving the red, green, and blue components of the video signals from each computer. To select the video output of a specific computer for display on the video monitor, a user inputs two video selecting signals into a control signal generating circuit. Depending upon the inputted video selecting signals, the control signal generating circuit produces an output signal corresponding to the selected video output. Thereafter, a control signal is generated that indexes the three sets of switches to switch the video signals being output by the desired computer to the single video monitor. The three sets of switches transfer the incoming video signals to three sets of switch circuits and current amplifying circuits that provide input and output impedance matching, respectively. The tuned video signals are then displayed on the single video monitor.
The Chen '148 patent, filed on Jul. 29, 1998 and issued on Sep. 12, 2000, discloses a video signal distributor that receives, processes, and distributes video signals received from one or more computers to a plurality of video monitors. The video signal distributor includes three transistor-based, voltage-amplifying circuits to individually amplify the red, green and blue video signals received from each computer prior to transmitting these signals to a video monitor. The video signal distributor also includes a synchronization signal buffering device that receives horizontal and vertical synchronization signals from each computer and generates new synchronization signals based upon the quantity of video signals that are output to the video monitors.
Fujii, filed on Feb. 10, 1998 and issued on Oct. 24, 2000, discloses a system for selectively operating a plurality of computers that are connected to one common video monitor. The Fujii system includes a data input device for entering data in any one of the plurality of connected computers. The system also includes a main control circuit, which is connected to the data input device, and a selection circuit for providing the entered data and receiving the video signals from the selected computer. A user selects a remote computer by supplying the command code associated with the desired remote computer utilizing the keyboard and/or mouse. A selection circuit receives the inputted commands and identifies the selected computer. The selection circuit then sends a signal indicative of the selected remote computer to a main control circuit, which provides communication between the keyboard, video monitor, and mouse and the selected remote computer.
Similar to Perholtz, Beasley, filed on Jun. 9, 2000 and issued on Feb. 5, 2002, discloses a specific implementation of a computerized switching system for coupling a local keyboard, mouse and/or video monitor to one of a plurality of remote computers. In particular, a first signal conditioning unit includes an on-screen programming circuit that displays a list of connected remote computers on the local video monitor. To activate the menu, a user depresses, for example, the “print screen” key on the local keyboard. The user selects the desired computer from the list using the local keyboard and/or mouse.
According to Beasley, the on-screen programming circuit requires at least two sets of tri-state buffers, a single on-screen processor, an internal synchronization generator, a synchronization switch, a synchronization polarizer, and overlay control logic. The first set of tri-state buffers couples the red, green, and blue components of the video signals received from the remote computer to the video monitor. That is, when the first set of tri-state buffers are energized, the red, green, and blue video signals are passed from the remote computer to the local video monitor through the tri-state buffers. When the first set of tri-state buffers are not active, the video signals from the remote computer are blocked. Similarly, the second set of tri-state buffers couples the outputs of the single on-screen processor to the video monitor. When the second set of tri-state buffers is energized, the video output of the on-screen programming circuit is displayed on the local video monitor. When the second set of tri-state buffers is not active, the video output from the on-screen programming circuit is blocked. Alternatively, if both sets of tri-state buffers are energized, the remote computer video signals are combined with the video signals generated by the on-screen processor prior to display on the local video monitor.
The on-screen programming circuit disclosed in Beasley also produces its own horizontal and vertical synchronization signals. To dictate which characters are displayed on the video monitor, the CPU sends instructional data to the on-screen processor. This causes the on-screen processor to retrieve characters from an internal video RAM for display on the local video monitor.
The overlaid video image produced by the on-screen processor, namely a Motorola MC141543 on-screen processor, is limited to the size and quantity of colors and characters that are available with the single on-screen processor. In other words, the Beasley system is designed to produce an overlaid video that is sized for a standard size computer monitor (i.e., not a wall-size or multiple monitor type video display) and is limited to the quantity of colors and characters provided by the single on-screen processor.
During operation of the Beasley system, a remote computer is chosen from the overlaid video display. Thereafter, the first signal conditioning unit receives keyboard and mouse signals from the local keyboard and mouse and generates a data packet for transmission to a central cross point switch. The cross point switch routes the data packet to the second signal conditioning unit, which is coupled to the selected remote computer. The second signal conditioning unit then routes the keyboard and mouse command signals to the keyboard and mouse connectors of the remote computer. Similarly, video signals produced by the remote computer are routed from the remote computer through the second signal conditioning unit, the cross point switch, and the first signal conditioning unit to the local video monitor. The horizontal and vertical synchronization video signals received from the remote computer are encoded on one of the red, green or blue video signals. This encoding reduces the quantity of cables required to transmit the video signals from the remote computer to the local video monitor.
Wilder, filed on May 5, 1998 and issued on Apr. 29, 2003, discloses a keyboard, video monitor, mouser and power (“KVMP”) switching system having an on screen display circuit that provides a visual means for accessing the KVMP switch. A first set of switching circuits coupled to a plurality of computers and the on screen display circuit allows a user to access and control any of the remote computers using a local keyboard, video monitor, and mouse. A second set of switching circuits coupled to the power supply of each remote computer and the on screen display circuit allows a user to control the electrical power to each remote computer. To select a remote computer using the Wilder system, a user activates the on-screen display by entering a “hot key” with either the keyboard and/or mouse. Initially, the on-screen display prompts the user to enter a username and password. After the user is verified, the user is provided a list of all attached remote computers. The user utilizes the local keyboard and mouse to select and control the power supply of the desired remote computer. Wilder incorporates a single on-screen processor for generation of the list of remote computers.
In view of the foregoing, a need clearly exists for a computer management system that is compatible with both standard size video monitors (e.g., monitors ranging from 13″ to 21″) and larger than standard size video monitors. In addition, a need clearly exists for a computer management system that provides an option menu that contains more characters and/or more colors than those available with a single on-screen processor. There is also a need for a computer management system having an option menu that provides greater flexibility and definition for identifying options and connected computers. Furthermore, there is a need for a computer management system that provides an option menu having a large quantity of available colors, which may be used to color code connected computers or options for purposes such as identifying the general location of each connected computer (e.g., connected computers having a blue description are located in Quadrant 1, connected computers having a green description are located in Quadrant 2, etc.). Furthermore, there exists a need for a computer management system that provides an option menu that allows the system user to choose the desired mode of operation (e.g., larger video display, more colors, more characters, etc.). Also, a need exists for a computer management system that provides an option menu that allows the system user to choose the size of the video monitor that is connected to the local user workstation.